Question $16.(6$ points$).$

Individuals diagnosed with a Leber's hereditary optic neuropathy are afflicted with blindness and cardiac defects. The pedigree of one family afflicted with this abnormality is presented below.

Answer the following questions:

a$.$ Explain the inheritance of this syndronge.

b$.$ Indicate by arrows the individual$($s$)$ in this pedigree that is $($are$)$ deceased.

c$.$ Encircle family members in generation III who are in danger of having children affected by Leber's abnormality.

Answer a